Urine biomarkers show secondhand smoke exposure highest among African-Americans
THURSDAY, March 1, 2018 (HealthDay News) — Urine screening for tobacco-specific biomarkers shows that nearly all economically disadvantaged urban adolescents are exposed to tobacco smoke, including secondhand smoke (SHS), according to a study published online Feb. 23 in Cancer Epidemiology, Biomarkers & Prevention.
Neal L. Benowitz, M.D., from the University of California, San Francisco, and colleagues compared 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and cotinine as biomarkers of exposure to tobacco in urban adolescents. This comparison was to determine the optimal NNAL cut-off point to distinguish active smoking (CS) from SHS exposure. Assays were conducted on surplus urine samples collected from 466 adolescents attending pediatric well or urgent care visits at Zuckerberg San Francisco General Hospital from June 2013 to May 2014.
The researchers found that 94 percent of adolescents had measurable levels of NNAL, compared to 87 percent for cotinine. To distinguish CS from SHS, the optimal NNAL cut-off point was 9.6 pg/mL by latent class or 14.4 pg/mL by receiver-operating characteristic analysis. Although there was a strong correlation between cotinine and NNAL, the correlation slopes differed for active versus SHS-exposed adolescents. NNAL levels were significantly higher in African-American nonsmokers compared with other groups, suggesting greater exposure to SHS.
“Routine biochemical screening with NNAL or cotinine detects high prevalence of SHS exposure and should be considered as a tool to reduce SHS exposure in high-risk populations,” the authors write.
One author disclosed financial ties to the pharmaceutical industry and has served as a paid expert witness against tobacco companies.
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